Apparatus for the production of music



Aug. 8, 1 939. B. F. MIESSNER APPARATUS FOR THE PRODUCTION OF MUSIC Filed April 28, 1937 2 Sheets-Sheet l e MW Y W M Ef R vfi m I N I. A m w w Aug. 8, 1939. a. F. MIESSNER APPARATUS FOR THE PRODUCTION OF MUSIC Filed April 28, 1957 2 Sheets-Sheet 2 IN V EN TOR.'-' f 7 ll proved means and methods 80- and control means in an Patented Aug. 8', 1939 UNITED STATES "PATENT oi-rlcr-i Benjamin Elliiessner, Millburn Township, Essex County, N. 1., assignor to Miessner Inventions, Inc., Millburn Township, Essex County, N. L, acorporation of New Jersey I Application Apr-i128, 1937, Serial No. 139,493 16 Claims. 01. 84-113) This invention relates music, and more particularly to that production from the vibrations of mechanical vibrators. It is a broadobject of the invention to provide im- It is an .allied object to provide an and improvements for a, musical instrument whose output tones are derived from the vibrations of such vibrators.

The invention has particular reference to the production of damped tones,.as from strictly continuous ones. It is an object to provide improved, means and methods production of damped musical tones, It is an 1 allied object to provide .an improved, and improvements for a, damped-tone musical instru-fment.

It .is another object to provide means and methods for control and regulation of the in- 20 divldual damping rates of the produced tones.

It is another object to provide improved means and methods for the control of the timbre or harmonic structure of the produced tones.

Still another object is the provision of .im-

proved means and methods for controlling the envelopes of the produced tones, including tone termination and particularly tone inception.

It is another object to provide improved arrangements of the vibrators and their exciting described. I

While not necessarily in all aspects limited thereto, the invention especially concerns the production of tones from the-vibrators by mechanico-electro-acoustic translation-i. e., thev translation ofthe mechanical vibrations first into electric oscillations and thence into sound. Particular objects of the inventionv are the fulillment of the above stated objects specifically in (0 such'an instrument.

.Other and allied objects will more fully appear from the following description and the appended claims.

In the description hereinafter set forth refer- 46 ence is had to the accompanying drawings, of

which:

Figure 1 is a partially elevational and partially schematic fractional view of an instrument embodying my invention in one form;

rFigure 2 is a like view .of an instrument embodying my invention in a modified'form;

Figure 3 is alike view .of an instrument embodying my invention in a further modified and somewhat elaborated form;

Figure 4a is an elevational view of an alternato the production of for such production.

improved,

distinguished for the instrument of the class I preferably th tlve arrangement of a the exciting means therefor;

plurality of vibrators and and Figure 4b is a cross-sectional view taken along the line 417-417 of Figure In U. s. Patent No. 2,001,302 issued July 9,

1935, to me,

I disclosed certain electrical and .electro-mechaniczil vibrating devices and systems for the impulse excitation into vibration of mechanical vibrators; purely typically, the vibrators were shown as output tone timbre by strings, and the excitation systems were arranged means of their controlling to provide control of the the vibrational waveforms oif the respective strings. According to hereinafter more fully the present invention, as appears, I may subject the vibrators to impulse excitation in any one of the manners shown in that patent, or otherwise; but

instead of employing plex waveform for the tive note, I may a single vibrator of comproduction of each respecfor each note rely on a plurality of simultaneously acting, harmonicaily related vibrators.

Broadly the simultaneous action of a plurality oi harmonically related vibrators is not new'with this invention;

multaneous action by but by effecting this sia simultaneous excitation of inherently damped vibrators, as well as by employing various hereinafter more able to achieve many spect of simplicity, flexibility, various controlling actions,

structures particularly described, I am and arrangements special advantages in reavailability for and the like.

Whileno unnecessary limitation thereto is intended, the vibrators according to the present invention are preferably of a type whose vibration is principally and of small harmonic development.

of fundamental frequency,

Typical of such vibrators are tuning forks, reeds (which last term I employ broadly as denoting a strip,

supported at one extremity, and

not in the restricted sense of an air-blown such device), and bars (for known nodal points of from each extremity) but non-limitative these three forms of of Figures 1, 2 and 3, figures I have shown tively,- charge or discharge illustration I vibrator in the instruments electrical impulse example supported at the about $6 of the bar length By way of alternative have shown respectively; and in these for exciting them, respecexcitation by condenser through electromagnets,

electrical impulse excitation-with otherwise limited current flow thr ough electromagnets, and

electro-mechanical excitation through a magnetically operated hammer.

translation features forms in one or more arealso Various control and shown in various of the figures. It is distinctly to be Understood, however, that these andother exciting. means may be interchanged in use with these and other vibrators, that any of the control and translation features is fully applicabl with any form of vibrator and any manner of impulse excitation, and that no limitations are intended of the broader aspects of the invention by reason of the particularly illustrated groupings. I

Reference being had to Figure 1, which fractionally shows a relatively simple instrument, there will be seen reeds la and lb (vertically arranged in the drawing) tuned for example to frequencies of two successive notes of the musical scale; it will be understood that this restricted showing is simply typical of a larger plurality of progressively tuned reeds. To the right of the reed Ia will be seen the reed Ia tuned to a higher frequency harmonically related to (for example, twice) that of the reed la, and to the right of the reed lb will be seen the reed lb bearing a corresponding, relation to the reed lb; it will be understood that the showing for each note of a pair of harmonically related reeds is simply typical of a. larger seriesof so-related reeds for each note.

Underneath the several reeds are shown the respective exciting electromagnets 2a, 2b, 2a, 2b. First terminals of all the electromagnets of the a series may be connected in common to the throw-contact 4a of a double-throw single-pole switch 3a; likewise first terminals of all the elec-' tromagnets of the b series may be connected in common to the throw-contact 4b of a like switch 3b; etc., it beingunderstood that an individual such switch will be provided for each note in the range of the instrument. The poles 6a, 6b, etc. of these switches may be connected to respective condensers 1a, 1b, etc., whose other sides are paralleled and connected to battery or other electrical energy source It); this connection may be to either terminal of the source III, as indicated schematically by the switch 9. The poles 6a, 612, etc. are normally thrown away from the throw-contacts 4a, 4b, etc. to touch their other throw contacts 5a, 5b,"etc.; each of the latter may be connected through a respective resistance brators for the note 8a, 8b, etc. to a first terminal ID of the source l0. Return circuits are provided, in manner hereinafter mentioned, from the second terminals of all the electromagnets to the second terminal ill" of the source I0.

Assuming the switch 9 adjusted as shown, to connect the condensers with the source terminal I0", each condenser will normally be maintained in a state of charge through the respective resistor, for example 8a or 8b; but upon downward throwing of the associated switch pole, for example 4a or 4b, the condenser will be discharged through all the electromagnets having similar letter designations to that of the pole so thrown. This provides simultaneous impulse excitation of all the harmonically related viwhose switch was so manipulated. The same ultimate effect is achieved if the switch 9 be adjusted to connect the condensers with the source terminal Ill, the difference being simply" that the condensers are then normally maintained discharged, and are charged through the appropriate electromagnets upon throwing of the note-switch. Insofar as the functioning of the exciting means in itself is concerned, it is quite similar't'o that disclosed be had in the In the instant case the return circuits, from.

the second terminals of the electromagnets to the source terminal l0", are made on the basis of individual partial tone components. Thus a return circuit ll is provided for the electromagnets 2a, 212, etc., which electromagnets are associated with the reeds tuned to the fundamental frequencies for the several notes; a return circuit ll is provided for the electromagnets 2a, 222', etc., which electromagnets are associated with the reeds tuned to the second partials of the several'notes; etc. In each of these return circuits is connected a control device for the several electromagnets of that circuit; these devices have been shown in Figure 1 as the respective variable resistances l2, l2, serially included in the respective return circuits. It will be appreciated that by the adjustment of these devices there will be fully controlled the relative strengths of the excitations of fundamental, second partial, etc. reeds which occur simultaneously upon throwing of any noteswitchand that this control will be at once uniformly effected for all notes.

In Figure 1 the reeds have been shown mounted to the fractionally illustrated bases I311, I312, l3a', l3b. or separate, and either rigid or of vibratile form. In the latter case the necessity for mechanicoelectro-acoustic translation of the reed vibrations is obviated by the direct mechanicoeacoustic translation so provided; this however, is simply :These bases may be either integral vibrations are translated into output tones, those tones will be controlled as to relative partial com:

ponent amplitudes and hence harmonic structure by the controls l2, l2 etc. abovementionecl.

In the instrument of Figure 2 the vibrators are shown as tuning forks 2|a, Zlb, H11, H17, following the same scheme of arrangement and frequency relationships as in the instrument of Figure 1. Also in correspondence with that instrument, exciting electromagnets 22a, 22b, 22a, 2222 are provided for the several vibrators; and again first terminals of all the electromagnets of the a series are paralleled, first terminals of all the electromagnets of the 1) series are paralleled, etc. These groups of paralleled terminals are shown, however, connected to the respective contact sp' gs 24a, 24b, etc. of respective normally open switches 23a, 23b, etc. These switches are formed by the springs just mentioned, and by respective weights 26a, 26b, etc. terminally secured on respective light springs 25a, 25b, etc. in'sulatedly spaced below the first-mentioned springs; the weights may normally rest on the rear extremities of the respective pivoted keys 21a, 28a, etc. Upon depression of the forward extremity of any key the respective weight will be moved upwardly; upon stoppage ofvthe key movement by impingement on its downstop (for example, 28a or 28b) the weight, in view of its momentum, will continue upwardly to touch the contact. sprin g thereabove-and to flex that spring and to remain incontact therewith, maintaining the switch closed, for a time dependent on the velocity of key movement. responsive action in itself is detailedly explained in the abovementioned patent in connection with each component; and

a-ies paa Figure 6 thereof, and reference maybe had thereto for a fuller consideration thereof. It is here used to excite simultaneously, with touchresponsive variations of length of a short current pulse, a plurality of brators.

All the weights 26a, 26b, etc may be connected, through the respective springs, 25a, 251), etc., to-

harmonically related 'vigether and to the terminal iii of source ll like The return I (e. g., 30, 30') of each may be connected the electentiometers 29, 29',

tromagnetreturns for all the vibrators for a particular p rtial component. It will be appreciated' that this control arrangement, though involving potentiometric rather than series resistance controls, is essentially the same in effect as that of Figure 1.

, .In Figure 2 mechanico-electro-acoustic translation .of the vibrator \ibrations into sound, with magnetic mechanicoeelectrlc translating devices, has been shown. Thus there will be seen, in slight spaced relationships to the several forks, the respective polarized pick-up electromagnets Ila,

Mb, 34a", flb'. These are connected to the input of a cascade which may typically comprise amplifier 32, potentiometer or volume control 33 (pedal operated, if desired), further amplifier I4, and loudspeaker or other ei'ectro-acoustic translating device 35, it being understood that by the cascade the oscillations translated by the pick-up eiectromagnets from the vibrator vibrations will be amplified, controlled in respect of overall amplitude or volume level, and translated into outputtones.

While the potentiometers 29, 29', etc., by controlling the relative strengths of excitations of the several vibrators for a singlefnote, provide an effective control have also shown in the instrument of Figure 2 certain harmonic structure controls appropriately incorporated in the translating means; these may be employed alternatively to the poetc., or additionally theretoin the latter case for example as a special means for shifting the harmonic structure during the continuance of a tone. These means are provided ,on the basis of individual partial tone components, by connecting together (e. g., in parallel) and across a potentiometer I! all the pickup electromagnets associated with vibrators tuned to the fundamental frequencies for the several notes; by connecting together and across a potentiometer 86' all the pick-up electromagnets associated with vibrators tuned to the secand partial components for the several notes; etc. Variable portions of the several potentiometers 36, 36, ries) and across the input of the cascade 32- 33-3l-45, for the application thereacross of tone-representing oscillations fully. controllable, in respect of relative strengths of the several partial components ofeach represented note, by these lsstsmentioued potentiometers-independently of or in addition to the control thereover by potentiometers 29, 29' etc. a

The, showings of instruments in Figures '1 and 2' do not illustrate such details as vibration tersecond terminals of the exciting.

'will operate as a over harmonic structure, 1

etc. areconnected together (e. g., in se-L minators (on-and-oif "dampers") for the vibrators, and the like, it being obvious how such may be applied thereto. I have, however, illustrated such terminators, as well as certain further special features over and above the showings of earlier figures, in the instrument of Figure 3. Herein the vibrators by way of example are 40b are shown as supports therefor of the character just described, suspending the bars from any suitable rigid members. For impulse excitation of the bars I have shown the respective electromagnetic hammer assemblies 42a, 42b, Ila, 4211', including respectively the coils 43a, 43b, 43a, 43b. Movable within the. coils are the respective suitably tipped and rod-shaped hammers a, b, a', Mb; these have been illustrated as comprising the respective insulating, non-magnetic portions 45a, 45b, 45a, 45b immediately adjacent the tips and normally lying principally withinthe coil length, and the respective magnetic portions 45a, 46b, 46a, lib extending downwardly from those insulating portions. It will be understood that upon' passage of a current pulse through any of the coils it solenoid to attract upwardly the associated magnetic hammer portion abovementioned, and thus to. cause a sudden upward movement of the entire hammer to strike the vibrator. This electro-mechanlcal vibrator exciting arrangement is in general similar to that disclosed in the .abovementioned patent in its Figure 2, excepting for the present desirable inclusion of the insulating hammer portions above-' mentioned.

2 of the patent abovementioned. First terminals of all thecoils (e. g., 43a, 43a) of the a series may be connected in common to one side of a normally open single-pole single-throw switch 41a; first terminals of all the coils (e. g., 43b, 43b) of the b series may be connected in common to one side of a like switch 41b; etc. The other sides of these switches are connected through respective condensers 48a, 48b, etc. to either terminal (through switch 9) of the source it, and also through respective resistances 49a, 48b, etc. to the source terminal I. Return circuits from the second terminals of the coils to the source terminal ll" are shown provided on the basis of individual partial componentsthrough potentiometers 29, 2!, etc. Just as the return circuits for the exciting electromagnetsin Figure 2. It will be understood that upon closing of any note switch (e. g "a or 41b) the associated condenser will be discharged or charged (according to the adjustment of switch 9) through the abovementioned coils associated with the several vibrators for that note; with this simplified switch there -will occur after the initial pulse a small continu'ed current fiow shown as metal bars supported at the nodal shown and described in connection with Figure It will also be, understood that by the adjustment of the movable contacts 30, 30', etc. of the potentiometers 29, 29', etc. there may be controlled,

as in the instruments of earlier figures, the relative excitation strengths and hence vibration amplitudes for the several vibrators for each note-'at once uniformly for all notes.

Vibration terminators are shown in the instrument of Figure 3 in the form of soft pads 50a, 50b, 50a, 50b normally resting on the respective vibrators, and attached to upwardly extending magnetic shanks Ma, am, Bib; and solenoids 52a, 52b, 52a, 52b for lifting the shanks and pads at appropriate times. One terminal of each of these solenoids may be grounded (i. e.,connected to some reference potential) the other terminals of all these solenoids of the a. series may be connected to a normally open single-pole single-throw switch 53a, the other terminals of all these solenoids of the 1) series to a normally open like switch 53b, etc. These switches are electrically connected through common battery or other current source 541 to ground; and each may be arranged for closure, to energize its respective solenoids, during the closure of the associated noteswitch (e. g., 370. or Mb) by an insulating tie (e. g., 55a, 55b) thereto. It will thus be understood that simultaneously with the closing of any note-switch the vibration terminators for the several associated vibrators will be lifted from the latter, will remain lifted throughout continued closure of the note-switch, and will fall again to stop the vibrations of those several vibrators upon release or opening of the noteswitch.

By way of example, the translation of the vibrator vibrations into sound in the instrument of Figure 3 has been shown as effected by capacitative mechanico-electric translation, followed of course by electro-acoustic translation. Thus in slight spaced relationships to the several vibrators may be provided the respective pick-up electrodes 56a, 56b, 55a, 55b, each typically in the form of an adjustable screw of large flat head; this provides to each vibrator a capacity which willbe varied by the vibration of the vibrator. All the vibrators may be grounded, as through one of each of the pairs of metallic cord supports, paralleling the vibrator sides of all these capacities.

A common conductor 51 may be provided for the electrode sides of all these capacities for vibrators for fundamental components, and each electrode (e. g., 56a, 56b) associated with such vibrators may be connected to this conductor (e. g., through the respective conductors 58a, 58b); a common conductor 51' may be provided for the electrode sides of all the capacities for vibrators for second partial components, and each electrode (e. g., 55a, 56b) associated with such vibrators may be connected to this conductor (e. g., through the respective conductors 58a, 58b); etc. Each of these conductors 51, ,51', etc. may be connected through a respective potentiometer 60, 60', etc., and through a common electrical potential source 59, to ground. This source will be of inaudible frequency poten-- tial-and the inaudible frequency may if desired be zero, in which case the potential is of course direct. In any event it will be understood that.

-' across the series combination of source 59 and potentiometer 60 will appear some potential from .34-35 of earlier figures.

the source modulated in accordance with the vibrations of the vibrators for fundamental frequency components; across the series combination of source 59 and potentiometer- 60', some potential from the source modulated in accordance with the vibrations of the vibrators for second partial components; etc. At least the modulations of these potentials may be applied in regulable amplitudes from the movable'contacts (e. g., 6|, 6|) of the several potentiometers through respective condensers (e. g., 62, 62') to a common load. This load may be the grid leak 63 of a repeater tube 54, in the output circuit of which may be connected the cascade 32-33 If the source 59 be of zero frequency, the tube 64 may be operated as a simple amplifier; otherwise it may beoperated as a demodulator, as will be understood. It will be appreciated that there is so provided translation of the vibrator vibrations into output tonesandcontrol in that translation of the harmonic structure of the tones, analogous to that effected by 36, 36', etc. in Figure 2 and, like that control, employable alternatively or additionally to the vibration amplitude control by 29, 29, etc,

The potentiometers 60, 60', etc. and the grid leak 63 are preferably of very high resistance or impedance value; and these, the condensers 62, 82', etc., the repeater tube 64, the pick-up electrodes, and the associated conductors (e. g., 57, 51', 58a, 58b, 58a, 58b, etc.) may be relatively susceptible to stray electrostatic fields. Accordingly grounded electrostatic shielding schematically indicated as 65 may be provided about these elements.

In instruments of the character disclosed herein I may provide means for reducing or eliminating certain tone characteristics immediately attendant upon tone inception-for example, not only sound immediately occasioned by or translated from the initial abrupt vibrator movement or the impact of the mechanical hammer (when employed), but also the sound translated from the first few cycles of-vibration of each vibrator when it is flexibly supported (as in Figure 3) and may require a short but finite time after excitation to stabilize in its proper position for vibration. Such tone envelope control means in their broadest aspects are known; but in Figure 3 I have shown them in the novel combination with flexibly suppor ed vibrators (in which they have the special utility just mentioned) and also in a novel form. This form is similar to that of known ones in that it suppresses the efliciency of translation at and about the instant 01 vibrator excitation, but it differs in that it is serially interposed in the oscillation-transmitting connection (e. g., 58a) to the translatingorpickup device, and in that it operates by variablecapacity action-being useful independently of the frequency of the potential from the source 59. It may be noted that claims to this novel form of tone envelope control broadly are'not made herein, as similar subject matter is disclosed and claimed in my'co-pending application Serial No. 208,357, filed May 17, 1938.

In Figure 3 will be seen two thin co-axial and longitudinally spaced rings 66a and 61a, surrounding the magnetic portion Ilia of the hammer,a for vibrator a when that hammer occupies its normal position; these rings have negligible direct mutual capacity (i. e., directly to each other), but a substantial mutual capacity through the hammer portion a when the hammer is normally positioned, and this capacity is serially interposed in the conductor "a by connection.of the two portions of that conductor to the two respective rings. Analogous rings, ana1-,

ogously connected, are provided in the case of each of the other vibrators, being designated ficiency are restored. The hammer may be prevented from bouncing at the conclusion of its rebound by employing for its downstop a weak permanent magnet (e. g., 4, 68b, 68a, 68b) on top of which a "non-magnetic bottom tip for the hammer may normally rest. The electrostatic shielding 65 should of course be extended to include all of the mentioned rings, and magnetic hammer portions when the latter are in their normal positions.

Another feature which I find it advantageous to incorporate in instruments of the-character described herein is a control of damping rates, both in an absolute sense, and on a relative basis as to different partial tone components. In Fisure 3 I show associated with each vibrator an individual damping means or dampen-which term I employ to denote a device for increasing damping rate throughout a given vibration, ratherthan to denote a means for stopping that vibration (such as the terminators abovementioned). These dampers have been shown for the respective vibrators as small felt or other damping rates,

vpads 89a, 69b,

partial compounds (e. g., 120.,

69a, 691), respectively supported on very light springs 10o, 'lllbfllia', 10b and thereby urged lightly against the bottoms of the respective vibrators in one or the nodal regions (i. e., only very close to a nodal point). Secured to the several such springs, and extending downwardly therefrom partially into the respective solenoids 120,121), 12a, 12b, are the respective magnetic shanks 1'0, Ha, Ha, Ha; first terminals of all the solenoids may be grounded. Second terminals of all the solenoids for vibrators for fundamental components (e. g., 12a, 1217) are connected to variable resistance 13; second terminals of all the solenoids for second 12b) are connected to'variableresistance I3; etc. The several such variable resistances may be connected in common through variable resistance 14 to the non-ground extremity of current source 54 abovementioned. The energization of the solenoids from'that source serves to reduce the pressures of the dampers against the vibrators or, when stronger, to eliminate those pressures by moving the dampers wholly out of contact with the vibrators; the pressure reduction or elimination may be adjusted for all the vibrators simultaneously by the resistance 14; and such reduction or elimination may be adjusted individually for each respective partial component group of vibrators by adjustment of the several resistances 13, 13', etc. Since the damping rate of each vibrator will depend inversely on this pressure, there are made available inversely corresponding adjustments of the tone and component and these of course are unified for the instrument as a wh l i manner co responding to the unification of the harmonic structure controls. Very striking tonal effects I may be secured by the damping at difierent rates of the various partial components of each tone.

It will be understood that the mechanical arrangements in which'I have shown my invention are purely typical, and that wide modifications may obviously be made therein. Thus in Figures 4a and 4b I have illustrated a grouping. of a plurality of. harmonically related vibrators 8|, for example of reed form, over a single exciting electromagnet 82 therefor, obviating the necessity for a plurality oflnterconnected exciting devices for the vibrators of a single note. By way of example, mechanico-electric translating electrodes ,83 frictionally appear above the several vibrators. mutually shielded as by shielding schematically indicated as 84.

And it will be understood that in still broader aspects my invention is not to be taken as unnecessarily limited by the details of the instruments specifically illustrated and described herein, these being necessarily illustrative and not comprehensive. The scope of my invention is rather to be gauged by the appended claims, wherein I undertake to set forth that scope as broadly as the state of the artwill permit. I claim:

1. A musical instrument for output tones of a A plurality of musical notes, having for each note a plurality of damped vibrators respectively tuned to a uniform several partial tone components; a plurality of impulse excitation means each for simultaneously exciting all the vibrators for a respective note into damped vibrations; and a plurality of single electrical control elements each for'correspondingly varying the harmonic structure of all the output tones in respect of a respective one of said partial tone components.

2. A musical instrument for output tones of a plurality of musical notes, having for each note a plurality of damped vibrators respectively tuned to a uniform several partial plurality of impulse excitation means each for simultaneously exciting all the vibrators for a tone components; a

respective note into damped vibrations; and proplurality of impulse excitation means each for simultaneously exciting all the vibrators for a respective note into damped vibrations; and controlmeans for varying the strengths of such excitation for all notes differentially as to the vibrators for the several said partial components.

4. In a musical'instrument for output tones of a plurality of musical notes, including a mechanico-electro-acoustic translating system: a plurality of damped vibrators for each note respectively tuned to a uniform several partial tone components, all the vibrators influencing said translating system; a plurality of impulse excitation means each for simultaneously exciting all the vibrators for a respective note into damped vibrations; and control means for varying the response of said translating system difierentially with respect to the vibrators for the several said partial components. r 5. In a musical instrument for output tones of a plurality of musical notes, including a plurality of mechanico-electric translating devices and load means responsive thereto: a plurality 'of damped vibrators for each note respectively tuned to a uniform several partial components, said translating devices being mechanically associated with said vibrators and electrically arranged in groups according to said partial components; a

plurality of impulse excitation means each for simultaneously exciting all the vibrators im a respective note into damped vibrations; and control means for varying the response of said load difi'erentially with respect to the several said translating device groups.

6. In a musical instrument for output tones of a plurality of musical notes, 'including a mechanico-electro-acoustic translating system: a plurality of damped vibrators for each note respectively tuned to a uniform several partial tone "components, all the vibrators influencing said translating system; impulse excitation means for each note for simultaneously exciting allthe vibrators therefor into damped vibrations; and distinct control means, respectively associated with said excitation means and with said translating system, 'each for varying the harmonic structure of the output tones.

, 7. A musical instrument comprising for a single note a plurality of damped vibrators of mumeans, associated withsaid vibrators and influencing the same throughout their vibrations, for varying the relative rates or damping of said vibrators.

9. A musical instrument comprising for a single note a plurality of damped vibrators of. mutualy diiierent, harmonically related irequencies;

' impulse excitation means for simultaneously exciting said vibrators; and decrement-control means, associated with said vibrators and influencing, the same throughout their vibrations, for jointly varyingthe rates of damping of said vi-- brators.

10. A musical instrument -for output tones of a plurality of musical notes, having for each note a plurality of damped vibrators respectively tuned to a uniform several partial components; impulse excitation means for. each note for simultaneously exciting all the vibrators therefor; and means associated with the several pluralities of vibrators for respectively different partial components and influencing the vibrators throughout their vibrations, for imparting respectively different damping rates to the several pluralities of vibrators for respectively different partial components.

11. A musical instrument for output tones of a plurality of musical notes, having for each note a plurality of damped vibrators respectively tuned to aunifcrm several partial components; impulse excitation means for each note for simultaneously exciting all the vibrators therefor; and decrement-control means, associated with said vibrators and influencing the same throughout their vibrations, for varying the relativerates of damping of the several pluralities of vibrators for respectively different partial components.

12. A musical instrument for output tones of a plurality of musical notes, having for each note a plurality of damped vibrators respectively tuned to a uniform several partial components; impulse excitation means for each note for simultaneously exciting all the vibrators therefor; and decrement-control means, associated with said vibrators and influencing the same throughout their vibrations, for jointly varying the damping rates 7 of all said vibrators.

13. In a musical instrument having a system for mechanico-electro-acoustic translation: a flexibly supported vibratorinfiuencingsaidsystem, impulse exciting means therefor, and means responsive to said exciting means for suppressing the efiiciency of said translation at and about the instant of excitation ofsaid vibrator.

14. In a musical-instrument having a mechanical vibrator: damping means biased against said vibrator throughout its vibration, and electromagnetic means for progressively varying the bias of said damping means against said vibrator.

15. In a musical instrument having a mechanico-electric translating electrode: a mechanical vibrator, and metallic cord means supporting said vibrator in slight spaced relationship to said electrode and providing an electrically conductive .connection to said vibrator.

16. In a musical instrument having for a single note mechanical means arranged for the'production of a complex damped output tone: impulse exciting means for said mechanical means, and decrement-control means, associated with said mechanical means and influencing the same,

throughout said tone production, for independently varying the damping rates of a plurality of partial components of. said tone.

BENJAMIN F. MIESSNER. 

